blow off valves/dump valves

obi_waynne

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On modern closed loop engine BOVs can cause a problem. Personally unless I was upping the boost I would leave alone. The sound they make is great though but not to everyones taste. A remap should be your first mod on a Turbo - in my humble opinion.
 

rip

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Cambridgeshire
waynne said:
On modern closed loop engine BOVs can cause a problem. Personally unless I was upping the boost I would leave alone. The sound they make is great though but not to everyones taste. A remap should be your first mod on a Turbo - in my humble opinion.

Thanks for that advice :)
 

gixxer6

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Lisburn. N.Ireland
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peugeot 207 thp 150
Hi, just joined, I have a xs sport 150 and have fitted a BOV. To date I have had no issues. However, I am considering a K&N induction kit. Anyone have pros and cons for this ??
 

prevtec

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ireland
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prelude 2.2vtec jap
i watched a thing 1 night and the mechanic said BOVs are bad for turbos
something to do with the turbo having to gather air everytime you change gear
turbos are supposed to have air in the system all the time

can someone explain to me is this right or wrong??
 

gixxer6

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Lisburn. N.Ireland
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peugeot 207 thp 150
have heard similar things to that, but also that they release the build up of pressure too. its hard to find a suitable answer to these questions. some recomend, some disaprove.
 

pgarner

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Lockerbie, SW Scotland
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Octy smoke machine
dont think it matters really on the turbo side it depends on the ECU some look for the extra air and provide the fuel for this. if these diverter valves are changed for a BOV then it overfuels.
Others dont look for this so the air is dumped to the air.

i personally would say diverter valves are better for 2 reasons.

1. Pressurised air is entering the turbo so spool up time in theroy should be faster - less lag
2. no loud Ppssssssssssssssssssstt everytime you change gear.

Granted no 2 is down to personal choise.

K and N kit will allow more air however theres alot of complaints about K&N over oiling the filters, the oil comes off and sticks to the MAF screwing it up.
 

Country Bumpkin

Track Warrior
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187
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Norfolk
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GTO T.T.
A recirculating dump valve is better for the engine in normal circumstances as it is not dumping air which has already been accounted for by the MAF and ECU.
Atmospheric dump valves can cause engine flutter when the foot is taken of the pedal as this air has been accounted for and all of a sudden it's not there.
Some engines will run richer when this happens due to the management system adding fuel to air that it believes is in the system when the reality is that it has been passed to the wild blue yonder.
We have dump valves/blow off valves or what even name people want to call them as they reduce pressure on the turbo's when the loud pedal is pressed again after gear change, backing off etc.
When i have time i'll do a proper write up on how this stuff works if anyone is interested, sorry, busy at work now so the above is very brief, off the top of my head . :)
 

turbonutter69

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Insignia SRI.
i watched a thing 1 night and the mechanic said BOVs are bad for turbos
something to do with the turbo having to gather air everytime you change gear
turbos are supposed to have air in the system all the time

can someone explain to me is this right or wrong??

A dump valve does get rid of some pressure but not all. A dump valve is designed to keep the turbo spinning which inturn helps it spool up quicker. Plus you get the all imporant whoooootish lol :bigsmile::bigsmile:
 

Wcnwzrd

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Casa Grande, Arizona
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95 300zx TT (RIP)
Personally i can't stand BOVs. my buddies and i will normally get a great laugh out of someone with one. A properly designed turbo system will already have the pressure issue accounted for, thus eliminating the need for a BOV. I would look into other options. True they cost a bit more and may take you a bit more time, but you will learn more about your car in the process.
 
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